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Cytokinesis illustration Ciliate undergoing cytokinesis, with the cleavage furrow being clearly visible. Cytokinesis (/ ˌ s aɪ t oʊ k ɪ ˈ n iː s ɪ s /) is the part of the cell division process and part of mitosis during which the cytoplasm of a single eukaryotic cell divides into two daughter cells.
Animal cells form an actin-myosin contractile ring within the equatorial region of the cell membrane that constricts to form the cleavage furrow. [1] In plant cells, Golgi vesicle secretions form a cell plate or septum on the equatorial plane of the cell wall by the action of microtubules of the phragmoplast . [ 2 ]
In animals the cytokinesis ends with formation of a contractile ring and thereafter a cleavage. But in plants it happen differently. At first a cell plate is formed and then a cell wall develops between the two daughter cells. [36] In Fission yeast the cytokinesis happens in G1 phase. [37]
The eukaryotic cell cycle consists of four distinct phases: G 1 phase, S phase (synthesis), G 2 phase (collectively known as interphase) and M phase (mitosis and cytokinesis). M phase is itself composed of two tightly coupled processes: mitosis, in which the cell's nucleus divides, and cytokinesis, in which the cell's cytoplasm and cell membrane divides forming two daughter cells.
In contrast to animals, fungi and non-vascular plants, the cells of flowering plants lack dynein motors. However, they contain a larger number of different kinesins. Many of these plant-specific kinesin groups are specialized for functions during plant cell mitosis. [11] Plant cells differ from animal cells in that they have a cell wall.
Transverse: Here cytokinesis takes place along the transverse axis. e.g. in ciliate protozoans like Paramecium. Oblique: In this type of binary fission, cytokinesis occurs obliquely. Example Ceratium. Binary fission means "division into two". It is the simplest and most common method of asexual reproduction.
This results in an unequal cytokinesis, in which both macromeres inherit part of the animal region of the egg, but only the bigger macromere inherits the vegetal region. [8] The second mechanism of unequal cleavage involves the production of an enucleate, membrane bound, cytoplasmic protrusion, called a polar lobe. [ 8 ]
After cytokinesis is complete, one of the two daughter cells inherits a remnant known as the midbody ring. [ 8 ] Activation of the cell-cycle kinase (e.g. Rho-kinases ) during telophase initiates constriction of the actomyosin ring by creating a groove that migrates in an inward motion.